Low-Dose Glyphosate Does Not Control Annual Bromes in the Northern Great Plains

2015 ◽  
Vol 8 (3) ◽  
pp. 334-340 ◽  
Author(s):  
Erin K. Espeland ◽  
Robert Kilian

AbstractAnnual bromes (downy brome and Japanese brome) have been shown to decrease perennial grass forage production and alter ecosystem functions in northern Great Plains rangelands. Large-scale chemical control might be a method for increasing rangeland forage production. Although fall application has been shown to be the most effective and least likely to impact co-occurring native species, spring germination of downy brome may reduce the efficacy of fall-only herbicide application. We assessed the impact of a low glyphosate dose rate (210 g ha−1) applied to rangelands in fall or in fall and spring on nontarget species and on annual brome abundance at two sites in eastern Montana over 2 yr. We tested the following hypotheses: (1) nontarget effects are greater with spring herbicide application, (2) fall and spring herbicide application are necessary for effective downy brome control, and (3) fall herbicide application is sufficient to control Japanese brome. Few nontarget effects occurred; two dicotyledonous species exhibited small increases in response to herbicide. We found that that a single fall application reduced downy brome cover and seed bank density, but after the second fall application in the following year, downy brome did not continue to show a response to herbicide. After 2 yr of fall herbicide application, Japanese brome had denser seed banks in plots where herbicide had been applied. Blanket glyphosate application on rangelands is an unreliable method for controlling annual brome invasions in the northern Great Plains.

1993 ◽  
Vol 73 (4) ◽  
pp. 765-778 ◽  
Author(s):  
W. D. Willms ◽  
P. G. Jefferson

The mixed prairie represents the most arid region of the Northern Great Plains in Canada. Approximately 6.5 M ha of the original total of 24 M ha have retained their native character. The native prairie supports about 5.3 M animal–unit–months or about 15% of all beef cattle present on the Canadian prairies. A large portion of the area is dominated by either needle-and-thread (Stipa comata Trin. + Rupr.) or western wheatgrass (Agropyron smithii Rydb.), both cool season grasses, and associated with blue grama [Bouteloua gracilis (H.B.K.) Lag. ex Steud.] a warm season grass. These species define the major plant communities of the mixed prairie and determine their production potential. However, their production is limited by available water during the growing season and by soil nutrients; factors which also influence their species composition. Grazing imposes a significant impact on the grasslands by altering the water and nutrient cycles, through defoliation and reduced plant litter, and eventually by affecting the species composition. Removing litter may reduce forage production by up to 60% and repeated defoliation will favour the more drought tolerant but less productive species. Forage production may be increased by seeding introduced species, which have a greater shoot to root ratio than native grasses, or with fertilizer application. Livestock production may be increased with the use of grazing systems. However, the benefits of each practice on the mixed prairie must be assessed in terms of their cost, their impact on the environment, and the reduced or lost value for other users. Key words: Biomass, above-ground, below-ground, water-use efficiency, reseeding, soil fertility, grazing efficiency


Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1060-1065 ◽  
Author(s):  
Z. Miller ◽  
F. Menalled ◽  
D. Ito ◽  
M. Moffet ◽  
M. Burrows

Plant genotype, age, size, and environmental factors can modify susceptibility and tolerance to disease. Understanding the individual and combined impacts of these factors is needed to define improved disease management strategies. In the case of Wheat streak mosaic virus (WSMV) in winter wheat, yield losses and plant susceptibility have been found to be greatest when the crop is exposed to the virus in the fall in the central and southern Great Plains. However, the seasonal dynamics of disease risk may be different in the northern Great Plains, a region characterized by a relatively cooler fall conditions, because temperature is known to modify plant–virus interactions. In a 2-year field study conducted in south-central Montana, we compared the impact of fall and spring WSMV inoculations on the susceptibility, tolerance, yield, and grain quality of 10 winter wheat varieties. Contrary to previous studies, resistance and yields were lower in the spring than in the fall inoculation. In all, 5 to 7% of fall-inoculated wheat plants were infected with WSMV and yields were often similar to uninoculated controls. Spring inoculation resulted in 45 to 57% infection and yields that were 15 to 32% lower than controls. Although all varieties were similarly susceptible to WSMV, variations in tolerance (i.e., yield losses following exposure to the virus) were observed. These results support observations that disease risk and impacts differ across the Great Plains. Possible mechanisms include variation in climate and in the genetic composition of winter wheat and WSMV across the region.


2016 ◽  
Vol 9 (4) ◽  
pp. 252-260 ◽  
Author(s):  
Rodney G. Lym

Quinclorac will control leafy spurge and not injure many established native grasses and forbs. Seeding of desirable species is often required to reestablish native vegetation after an invasive weed-management program, but quinclorac residue may inhibit the reestablishment of native species. Greenhouse studies were conducted to estimate quinclorac dissipation rates in Northern Great Plains soils and the effect of residue on establishment of some native grass and broadleaf plants. Quinclorac 50% dissipation time (DT50) ranged from > 21 to 112 d in four soils from the Northern Great Plains. The quinclorac DT50 was dependent on several factors including soil type, moisture content, temperature, and especially organic matter (OM). Across four different soil textures, quinclorac dissipation generally increased as soil moisture content increased, but moisture had less of an impact in low OM soils. Quinclorac dissipation also increased as temperature increased in the four soils. The most rapid dissipation occurred in soils with higher OM (> 6%), with an average DT50 of < 38 d, at 45% moisture content, held at 16 C. Wild bergamot, purple coneflower, blanketflower, and stiff goldenrod seedling growth were all reduced by quinclorac residue at 6 μg kg−1, the lowest concentration evaluated in the study. The native grass species big bluestem, intermediate wheatgrass, and switchgrass generally were tolerant of quinclorac, but green needlegrass was sensitive, and seedling growth declined as quinclorac residue increased from 6 to 375 μg kg−1. Based on a quinclorac application of 840 kg ha−1 and 150 frost-free d, seeding of sensitive forbs and grasses should be delayed at least 12 mo after herbicide application.


1998 ◽  
Vol 12 (2) ◽  
pp. 381-390 ◽  
Author(s):  
Robert A. Masters ◽  
Scott J. Nissen

Degradation of Great Plains rangelands can be linked to past management practices that reduced native species diversity and accelerated establishment and expansion of exotic weeds and less desirable native species. Leafy spurge is an exotic perennial weed that infests more than 1 million ha in the northern Great Plains and reduces rangeland carrying capacity by competing with desirable forages and causing infested areas to be undesirable to cattle and wildlife. Research was conducted to determine the feasibility of using herbicides to suppress leafy spurge and other resident vegetation, which facilitated planting and establishment of native tallgrasses. Four experiments were conducted where 0.28, 0.56, and 0.84 kg ai/ha imazapyr and 0.1 kg ai/ha sulfometuron were applied alone and in combination and 0.84 kg ai/ha glyphosate was applied to leafy spurge-infested range sites in fall 1991 near Ainsworth, NE, and in fall 1991, 1992, and 1993 near Ansley, NE. Research areas were burned about 200 d after herbicide application to reduce plant residue. Monoculture stands of big bluestem and switchgrass were then no-till planted in each experiment and indiangrass was no-till planted in experiments initiated at Ansley in 1992 and 1993. Yields of the planted grasses, leafy spurge, and other vegetation were measured in August at each location starting the year after planting. Imazapyr was an essential component of treatments applied before planting to facilitate establishment of highly productive stands of the tallgrasses. Generally, yields were maximized by fall treatments of 0.28 kg/ha imazapyr + 0.1 kg/ha sulfometuron for big bluestem, 0.84 kg/ha imazapyr for indiangrass, and 0.84 kg/ha imazapyr + 0.1 kg/ha sulfometuron for switchgrass. Yields of the planted grasses were frequently four times greater where these herbicides were applied compared to where glyphosate or no herbicide were applied. Leafy spurge yields were usually reduced in areas where tallgrass yields were greatest. The sequential combination of suppressing vegetation with fall-applied herbicides, burning standing dead plant residue, then no-till planting desirable native tallgrasses in the spring increased productivity of these leafy spurge-infested range sites.


2009 ◽  
Vol 89 (2) ◽  
pp. 281-288 ◽  
Author(s):  
P. M. Carr ◽  
G. B. Martin ◽  
R. D. Horsley

Tillage is being reduced in semiarid regions. The impact of changing tillage practices on field pea (Pisum sativum L.) performance has not been considered in a major pea-producing area within the US northern Great Plains. A study was conducted from 2000 through 2005 to determine how field pea performance compared following spring wheat (Triticum aestivum L.) in clean-till (CT), reduced-till (RT), and no-till (NT) systems arranged in a randomized complete block at Dickinson in southwestern North Dakota. Seed yield increased over 1600 kg ha-1 in 2000 and almost 400 kg ha-1 in 2003 under NT compared with CT, and by 960 kg ha-1 in 2000 under NT compared with RT (P < 0.05). Differences in seed yield were not detected between tillage systems in other years. Plant establishment was improved as tillage was reduced, averaging 66 plants m-2 under NT and RT compared with 60 plants m-2 under CT management. The soil water conservation that can occur after adopting NT may explain the increased seed yields that occurred in some years. These results suggest that field pea seed yield can be increased by eliminating tillage in semiarid areas of the US northern Great Plains, particularly when dry conditions develop and persist. Key words: Zero tillage, field pea, cropping system, N-fixation, legume


2013 ◽  
Vol 93 (5) ◽  
pp. 793-798 ◽  
Author(s):  
M. P. Schellenberg ◽  
B. Biligetu ◽  
Y. Wei

Schellenberg, M. P., Biligetu, B. and Wei, Y. 2013. Predicting seed germination of slender wheatgrass [Elymus trachycaulus (Link) Gould subsp. trachycaulus] using thermal and hydro time models. Can. J. Plant Sci. 93: 793–798. Slender wheatgrass [Elymus trachycaulus (Link) Gould subsp. trachycaulus] is a native caespitose grass used for forage production and reclamation. The objective of this study was to quantify seed germination requirements of slender wheatgrass using thermal and hydro time models. Slender wheatgrass, San Luis, had a base temperature (Tb) of 9.48°C, and required 946.8°C h to reach 50% of seed germination. Seed germination of San Lius occurred at a temperature range of 10–30°C, with the highest germination rate being achieved at 20°C, and the highest final germination percentage being achieved at 25°C. At 20 and 25°C, San Luis had a hydro time constant of 61 MPa h, and a median base water potential of approximately 1.0 MPa, but the germination had low uniformity in reduced water potentials. Final germination was reduced at or lower than –0.6 MPa. Compared with many other cool-season native grasses of Northern Great Plains, a relatively warm temperature would be necessary for uniform seedling establishment of this grass. In reclamation seeding, the seedling emergence could reach the highest level at a temperature of 25°C.


2018 ◽  
Vol 33 (1) ◽  
pp. 192-195
Author(s):  
Walter H. Fick ◽  
Keith Harmoney

AbstractGreat Plains yucca is a native species that competes with forage plants for space and water and at high densities may warrant control. The objective of this study was to determine the efficacy of seven herbicides applied in the spring or fall for Great Plains yucca control. Six foliar herbicides applied by ground application at 187 L ha−1 spray volume, one herbicide applied to individual plant whorls, and a nontreated check were established in June and September of 2009 and 2011. Percent mortality was determined 12 to 16 mo after herbicide application. Most herbicides gave similar control between the 2 yr, with triclopyr in diesel applied to individual plant whorls at 10 g L−1 providing the greatest control at 83%. Most herbicides applied in June near the blooming stage of Great Plains yucca were more effective than September treatments. June treatments providing the greatest reduction in yucca densities were metsulfuron + dicamba + 2,4-D amine + 2,4-D low volatile ester (LVE) at 21 + 113 + 325 + 431 g ae ha−1, metsulfuron + aminopyralid + triclopyr at 49 + 9 + 227 g ha−1, metsulfuron + chlorsulfuron + 2,4-D LVE at 34 + 11 + 431 g ha−1, and metsulfuron + aminopyralid + 2,4-D LVE at 49 + 9 + 431 g ha−1. A single application of a foliar herbicide provided a maximum of 72% mortality of Great Plains yucca, suggesting that repeat application may be necessary to achieve optimum control.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 817
Author(s):  
Rakhi Palit ◽  
Greta Gramig ◽  
Edward S. DeKeyser

Kentucky bluegrass (Poa pratensis L.) is one of the most aggressive grasses invading Northern Great Plains (NGP) grasslands, resulting in substantial native species losses. Highly diverse grasslands dominated by native species are gradually transforming into rangelands largely dominated by non-native Kentucky bluegrass. Several factors potentially associated with Kentucky bluegrass invasions, including high propagule pressure, thatch formation, climate change, and increasing nitrogen deposition, could determine the future dominance and spread of Kentucky bluegrass in the NGP. Because atmospheric CO2 is amplifying rapidly, a C3 grass like Kentucky bluegrass might be photosynthetically more efficient than native C4 grasses. As this exotic species shares similar morphological and phenological traits with many native cool-season grasses, controlling it with traditional management practices such as prescribed fire, grazing, herbicides, or combinations of these practices may also impair the growth of native species. Thus, developing effective management practices to combat Kentucky bluegrass spread while facilitating the native species cover is essential. Modifying traditional techniques and embracing science-based adaptive management tools that focus on the ecological interactions of Kentucky bluegrass with the surrounding native species could achieve these desired management goals. Enhancement of the competitiveness of surrounding native species could also be an important consideration for controlling this invasive species.


Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 240
Author(s):  
Graham R. S. Collier ◽  
Dean M. Spaner ◽  
Robert J. Graf ◽  
Brian L. Beres

Ultra-early seeding of spring wheat (Triticum aestivum L.) on the northern Great Plains can increase grain yield and grain yield stability compared to current spring wheat planting systems. Field trials were conducted in western Canada from 2015 to 2018 to evaluate the impact of optimal agronomic management on grain yield, quality, and stability in ultra-early wheat seeding systems. Four planting times initiated by soil temperature triggers were evaluated. The earliest planting was triggered when soils reached 0–2.5 °C at a 5 cm depth, with the subsequent three plantings completed at 2.5 °C intervals up to soil temperatures of 10 °C. Two spring wheat lines were seeded at each planting date at two seeding depths (2.5 and 5 cm), and two seeding rates (200 and 400 seeds m−2). The greatest grain yield and stability occurred from combinations of the earliest seeding dates, high seeding rate, and shallow seeding depth; wheat line did not influence grain yield. Grain protein content was greater at later seeding dates; however, the greater grain yield at earlier seeding dates resulted in more protein production per unit area. Despite extreme ambient air temperatures below 0 °C after planting, plant survival was not reduced at the earliest seeding dates. Planting wheat as soon as feasible after soil temperatures reach 0 °C, and prior to soils reaching 7.5–10 °C, at an optimal seeding rate and shallow seeding depth increased grain yield and stability compared to current seeding practices. Adopting ultra-early wheat seeding systems on the northern Great Plains will lead to additional grain yield benefits as climate change continues to increase annual average growing season temperatures.


Weed Science ◽  
2021 ◽  
pp. 1-69
Author(s):  
Amit J. Jhala ◽  
Hugh J. Beckie ◽  
Thomas J. Peters ◽  
A. Stanley Culpepper ◽  
Jason K. Norsworthy

Abstract Since the commercialization of herbicide-resistant (HR) crops, primarily glyphosate-resistant (GR) crops, their adoption increased rapidly. Multiple HR traits in crops such as canola (Brassica napus L.), corn (Zea mays L.), cotton (Gossypium hirsutum L.), and soybean [Glycine max (L.) Merr.] are available in recent years, and management of their volunteers need attention to prevent interference and yield loss in rotational crops. The objectives of this review were to summarize HR crop traits in barley (Hordeum vulgare L.), canola, corn, cotton, rice (Oryza sativa L.), soybean, sugarbeet (Beta vulgaris L.), and wheat (Triticum aestivum L.); assess their potential for volunteerism; and review existing literature on the interference of HR crop volunteers, yield loss, and their management in rotational crops. Herbicide-resistant crop volunteers are problem weeds in agronomic cropping systems, and the impact of volunteerism depends on several factors such as crop grown in rotation, the density of volunteers, management practices, and micro-climate. Interference of imidazolinone-resistant (IR) barley or wheat volunteers can be a problem in rotational crops, particularly when IR crops such as canola or wheat are grown. Herbicide-resistant canola volunteers are abundant in the Northern Great Plains due to high fecundity, seed loss before or during harvest, secondary seed dormancy, and can interfere in crops grown in rotation such as flax (Linum usitatissimum L.), field peas (Pisum sativum L.), and soybean. Herbicide-resistant corn volunteers are competitive in crops grown in rotation such as corn, cotton, soybean, and sugarbeet, with yield loss depending on the density of HR corn volunteers. Volunteers of HR cotton, rice, soybean, and sugarbeet are not major concerns and can be controlled with existing herbicides. Herbicide options would be limited if the crop volunteers are multiple HR; therefore, a record-keeping of cultivar planted the previous year and selecting herbicide is important. The increasing use of 2,4-D, dicamba, glufosinate, and glyphosate in North American cropping systems requires research on herbicide interactions and alternative herbicides or methods for controlling multiple HR crop volunteers.


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